KR20100137321A - Dome shaped piezoelectric linear motor - Google Patents

Abstract

PURPOSE: A dome shaped linear piezoelectric motor is provided to reduce a manufacturing process caused by adding an elastic body by forming a piezoelectric ceramic into a dome shape without a separate elastic plate in order to obtain vibration displacement. CONSTITUTION: A different electrode is applied to both sides of dome shaped piezoelectric ceramic actuator(100). A stick type or a shaft type vibration shaft(120) is vertically to fixed to the vertex of a dome shaped upper part. A cylindrical moving body(130) is inserted into the vibration shaft. A silicon rubber(140) is formed in the contact region between the surface of the mobbing body and the vibration shaft in order to maintain uniform frictional force. A wire respectively interlinks the power and both sides of the piezoelectric ceramics actuator. A solder(150) clinches the wire on both sides of the piezoelectric ceramics actuator.

Description

Dome-shaped linear piezoelectric motor {DOME SHAPED PIEZOELECTRIC LINEAR MOTOR}

The present invention relates to a linear piezoelectric motor that employs a dome-shaped piezoelectric ceramic actuator to provide an improved vibration displacement than the vibration displacement by a conventional piezoelectric ceramic.

Piezoelectric motor (Piezoelectric motor) is a next-generation motor using the piezoelectric effect of the piezoelectric ceramic actuator that vibrates according to the change of the applied electric field, refers to a noiseless motor having a driving frequency of 20kHz or higher ultrasonic range that cannot be detected by the human ear. Also called an ultrasonic motor. Piezoelectric motors have 3kg · cm generation force, 0.1ms or less, 10 times smaller size, and 0.1m or less accuracy, compared to conventional electromagnetic motors. It is widely used in applications requiring high levels of torque and low speed, such as driving a pickup lens or driving a pickup lens of a CD / DVD-ROM drive.

In general, piezoelectric motors may be implemented by a vibration transmission method such as a flexural wave type or a standing wave type, but the vibration transmission method may have a constant amplitude due to abrasion of contact parts when driven continuously. There was a disadvantage that is difficult to secure.

As an alternative to overcome this disadvantage, the linear piezoelectric motor is characterized in that the piezoelectric thick film is adhered to both sides of the metal elastic body with an adhesive, and then connected in parallel so that the bending motion is used as the driving source. Proposed.

The piezoelectric motor has a small size and relatively simple manufacturing process compared to the prior art has the advantage of providing a fast operating speed, the piezoelectric ceramic actuator had to bond a separate metal elastic plate in order to improve the displacement. Therefore, there is a problem that the manufacturing cost increases and the manufacturing process is complicated. In addition, since the piezoelectric thick film of 100 µm is used, it is weak to impact, has a small generation force, and has a problem of peeling the metal elastic plate and the piezoelectric thick film due to vibration of the piezoelectric thick film.

In addition, according to the prior art, since the vibration displacement of the moving shaft and the moving body is limited to a certain size, there is a problem in that the range of products to which the motor can be applied is limited.

The present invention has been proposed to solve the above problems, by ensuring a vibration displacement without bonding a separate elastic plate to the piezoelectric ceramic actuator, by providing an improved linear vibration displacement compared to the planar piezoelectric ceramic actuator It is an object of the present invention to provide a dome-shaped linear piezoelectric motor which can increase the operating efficiency of the linear piezoelectric motor and further expand its application range.

The dome-shaped linear piezoelectric motor (DSPLM) according to the present invention comprises a dome-shaped piezoelectric ceramic actuator treated to apply different electrodes on both sides, a rod-shaped vibration shaft fixed perpendicular to the upper apex of the dome shape, and a cylindrical shape. It is characterized in that it comprises a ceramic restrained body which is fitted to the vibrating shaft, and is fixed to the lower edge portion of the dome shape and the movable body to be linear movement along the vibrating shaft.

Here, the pressing member is formed on the surface of the movable body to maintain a constant frictional force on the contact portion between the movable body and the vibration shaft, wherein the ceramic restraint body is formed integrally with the piezoelectric ceramic actuator The ceramic restraint body has a rigidity capable of constraining the radial vibration of the piezoelectric ceramic actuator, and is formed of a material having a thermal expansion coefficient similar to that of the piezoelectric ceramic actuator. Is characterized in that the disk or ring shape is formed, the ceramic restraint is characterized in that coupled to the piezoelectric ceramic actuator by a thermosetting adhesive.

The present invention has the advantage that the manufacturing process due to the addition of the elastic body is shortened, the manufacturing cost is lowered because only the piezoelectric ceramics do not need to provide a separate elastic plate to obtain a vibration displacement, the manufacturing cost is lowered, conventional planar piezoelectric ceramics Compared to this case, the vibration displacement, the operating range and the generating force of the linear piezoelectric motor can be improved, thereby increasing the application range of the product to which the motor is applied.

The dome-shaped linear piezoelectric motor (DSPLM) according to the present invention comprises a dome-shaped piezoelectric ceramic actuator treated to apply different electrodes on both sides, a rod-shaped vibration shaft fixed perpendicular to the upper apex of the dome shape, and a cylindrical shape. And a ceramic restraint body fitted to the vibration shaft and fixed to the lower edge portion of the dome shape, the movable body being configured to linearly move along the vibration shaft.

Here, the movable body is moved along the direction of movement of the vibrating shaft when the inertial force of the movable body is smaller than the frictional force with the vibrating shaft when the vibrating shaft moves.

In addition, while a constant frictional force is maintained at a contact portion between the movable body and the vibration shaft through a predetermined pressing member, the displacement of the piezoelectric ceramic actuator of the dome shape in the ceramic restraint body can be maximized.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings, the same components in addition to the reference numerals for the components of each drawing as much as possible even if shown on different drawings Note that the same sign is used.

In the present invention, forming the dome-shaped piezoelectric ceramic actuator is to improve the displacement of the piezoelectric ceramic actuator. This type of piezoelectric motor is referred to as a dome-shaped piezoelectric linear motor (DSPLM), and the schematic form will be described with reference to the following photograph.

1 is a photo schematically showing a dome-shaped linear piezoelectric motor (DSPLM).

Referring to FIG. 1, a dome-shaped piezoelectric ceramic actuator 10 is provided, and a vibration shaft 20 having a shaft shape is formed at an upper vertex of the dome shape. At this time, the vibration shaft 20 may be fixed by the epoxy bond.

Next, a movable body 30 is formed at the center of the oscillation shaft 20, and the silicone rubber 40 is provided as an urging member outside the movable body 30.

Next, a solder 50 is formed on the surface of the dome-shaped piezoelectric ceramic actuator to which an electric wire for applying an electric field is connected.

When an electric field U is applied to the upper and lower surfaces of the piezoelectric ceramic actuator 10 described above, the compressive force or the stretching force is applied to the piezoelectric ceramic actuator 10 by the reverse piezoelectric effect.

That is, the piezoelectric ceramic actuator 10 according to the present invention is configured in a dome shape in which different electrodes are applied to both surfaces thereof, and a vibration shaft according to a polarity change of a voltage applied to both surfaces of the piezoelectric ceramic actuator 10. It vibrates in a manner that protrudes or indents in the direction of (20).

Here, the present invention introduces the principle of maximizing the effect of the vibration generated in the dome-shaped apex by introducing a ceramic restraint in the dome-shaped edge portion.

2A and 2B are photos and cross-sectional views schematically showing a dome-shaped linear piezoelectric motor DSPLM according to the present invention.

Referring to FIGS. 2A and 2B, a doped piezoelectric ceramic actuator 100 which is treated to apply different electrodes on both surfaces thereof is provided, and a rod-shaped or shaft-shaped oscillating shaft fixed vertically to the upper apex of the dome shape ( 120).

Then, the movable body 130 is fitted to the vibration shaft 120 in a cylindrical shape, the silicon rubber 140 as a pressing member to maintain a constant frictional force on the contact portion with the vibration shaft 120 on the surface of the movable body 130. Is provided.

Next, a power source for applying an electric field to the piezoelectric ceramic actuator 100, a wire connecting the both sides of the power source and the piezoelectric ceramic actuator 100, respectively, and a solder fixing the wires on both sides of the piezoelectric ceramic actuator 100 ( 150).

Next, as a main feature of the present invention, a ceramic restraint 160 is provided at the lower edge portion of the dome shape.

Here, it is preferable that the ceramic restrainer 160 is formed to be integrally formed with the piezoelectric ceramic actuator 100 by being bonded by a thermosetting adhesive, and to be formed in a disk shape or a ring shape as can be seen in the cross-sectional shape. . In the present invention, by forming the ceramic restraint 160 as described above, the displacement that is changed in the vicinity of the top of the dome shape can be maximized.

In addition, the ceramic restrainer 160 may have a rigidity capable of constraining the radial vibration of the piezoelectric ceramic actuator 100, and may be formed of a material having a similar thermal expansion coefficient to that of the piezoelectric ceramic actuator. In addition, the ceramic restraint 160 is integrally bonded by a thermosetting adhesive such as an epoxy bond. In this case, it is preferable to use a material in which the ceramic restraint 160 may not be destroyed during the thermosetting process.

Hereinafter, the principle of generating vibration (or the principle of generating vibration displacement) in the dome-shaped piezoelectric ceramic actuator and the effect of the ceramic restraint according to the present invention will be described in more detail with reference to the accompanying drawings.

3 is a three-dimensional structural diagram for analysis of the dome-shaped piezoelectric actuator according to the present invention, Figure 4 is a structural diagram for the finite element analysis (Finite Element meshes (FEM)) for the dome-shaped piezoelectric actuator according to the present invention.

3 and 4, the direction of the force on the dome-shaped piezoelectric ceramic can be seen schematically. That is, when the peak portion of the piezoelectric ceramic actuator constituting the piezoelectric ceramic contracts in the vibration axis direction, expands in the edge direction, and the thickness of the dome becomes thin, the microelements around the axis are compressed by the adjacent microelements. The force of the compressive force acts in the direction of the shaft's protrusion, and consequently, the central vertex portion of the piezoelectric ceramic actuator protrudes. At this time, it can be seen that the microelements are arranged in an annular direction toward the center of the axis.

Next, when the piezoelectric ceramic constituting the piezoelectric ceramic actuator expands in the vibration axis direction and contracts in the edge direction to increase the thickness of the dome, the microelements centered on the vibration axis are subjected to the force in the opposite direction as in the above case. The combined force of 작용 acts in the opposite direction of the projecting direction of the oscillation axis, resulting in the indentation of the center vertex portion of the piezoelectric ceramic actuator.

Here, the diameter of the dome-type piezoelectric ceramic actuator was 9.86 mm, the curvature was 4.6 mm, the thickness was 0.4 mm, and the piezoelectric material of PZT 5A was used, and when the FEM modeling was performed, the piezoelectric, dielectric and elastic properties of the following [Table 1] were used. You can use constants to get the result.

TABLE 1

s ₁₁ ^E s ₁₂ ^E s ₁₃ ^E s ₃₃ ^E s ₄₄ ^E 16.4 * 10 ^-12 m ² / N -5.74 * 10 ^-12 m ² / N -7.22 * 10 ^-12 m ² / N 18.8 * 10 ^-12 m ² / N 47.5 * 10 ^-12 m ² / N d ₁₅ d ₃₁ d ₃₃ ε ₁₁ ^T / ε ⁰ ε ₁₁ ^T / ε ⁰ 584 * 10 ^-12 C / N -171 * 10 ^-12 C / N 374 * 10 ^-12 C / N 1730 1700

5 is a graph showing a simulated impedance vs. frequency curve for a dome shaped linear piezoelectric motor (DSPLM) according to a comparative example of the present invention, and FIG. 6 is a dome shaped linear piezoelectric motor according to an embodiment of the present invention. A graph showing the simulated impedance versus frequency curve for DSPLM).

7 is an ATILA three-dimensional simulation result of applying a resonance frequency to a dome-shaped linear piezoelectric motor (DSPLM) according to a comparative example of the present invention, Figure 8 is a dome-shaped linear piezoelectric according to an embodiment of the present invention The result of ATILA 3D simulation by applying the resonance frequency to the motor (DSPLM).

In the above case, the results of the simulation under the assumption that there is no separate constraint on the piezoelectric ceramic actuator can be seen in FIGS. 5 and 7. The results of the simulation after the ceramic restraint is mounted are shown in FIGS. It can be seen in FIG.

Figure 5 shows the impedance versus frequency curve measured by the length of the shaft (shaft) 15mm, 20mm, 30mm, where the change in the impedance can be represented by approximately 2 parts, the first 84.0 ~ 87.6kHz There is a part showing, and there is a part showing 205.5 ~ 206.8kHz. In this case, referring to FIG. 7, it can be seen that the first part is a vibration mode with respect to the Z-axis, and the second part is a vibration displacement by the radial vibration mode.

When an electric field of 70 V _{p -p} is applied, it can be seen that the vibration displacement with respect to the Z-axis is ± 0.657 µm and the vibration displacement with respect to the radius is ± 3.576 µm. That is, when there is no restrainer on the edge portion of the dome-type piezoelectric ceramic actuator, the vibration displacement in the radial vibration mode is larger than the vibration displacement in the vibration axis direction.

On the other hand, in the case of Figures 6 and 8 according to a preferred embodiment of the present invention, by including a ceramic restraint at the bottom, the vibration displacement by the Z-axis vibration mode is ± 6.72㎛ to obtain an excellent vibration displacement expansion effect do. In addition, the vibration displacement by the radial vibration mode in the above case is represented by ± 2.499㎛, which is similar in magnitude to the vibration displacement with respect to the Z-axis in the case of Figure 5, including the ceramic restraint according to the present invention In the dome-shaped linear piezoelectric motor, it can be seen that the overall vibration displacement (vibration axial vibration displacement, radial vibration displacement) increases at the same applied voltage.

9 is a graph showing the maximum vibration and applied voltage for the dome-shaped linear piezoelectric motor (DSPLM) according to an embodiment of the present invention.

FIG. 9 shows experimental results of an embodiment of manufacturing a dome-shaped piezoelectric ceramic actuator using a PIM process using a soft PZT and 0.0 ₄ Pb (Sb _0.5 Nb _0.5 ) O ₃ -0.46PbTiO ₃ -0.5PbZrO ₃ composition. It is shown. At this time, the dielectric properties at room temperature is d ₃₃ ~ 550pC / N, piezoelectric properties k ₃₃ ^T ~ 1450, k _p = 0.7, Curie temperature is T _c = 320, the diameter of the dome-shaped piezoelectric actuator is 9.86 mm, the curvature was 4.53 mm and the thickness was 0.4 mm.

First, the silver paste (Metech Inc. # 3288) sintered at 650 ° C. for 30 minutes was ground and electrodelized to form a sintered specimen for electrochemical characterization. Next, after dropping the sintered specimen in an oil bath at 150 ℃ was measured by applying a DC field of 2.5kV / mm for 40 minutes. The vibrating shaft is then adhered to the upper apex portion of the dome-shaped piezoelectric ceramic actuator.

Next, in order to compare the experimental data with the simulation results of FIGS. 5 to 8, a micro laser interferometer (Cannon, DS-80A) having a resolution of 0.08 nm was used for the first vibration displacement portion. The electrochemical displacement characteristics of the piezoelectric ceramic actuator according to the present invention were measured. As a result of the measurement, the square wave electric field is applied to the sample, and the voltage of the positive waveform is applied at 50 kHz.

As described above, the domed piezoelectric ceramic actuator of the present invention produced by the PIM process exhibits a large tip vibration displacement, such as 7.84 mu m, despite its small size. The low electric field at this time is 87.5V _op / mm and is the result of FEM analysis. Therefore, the dome-shaped linear piezoelectric motor of the present invention manufactured by the PIM process exhibits excellent vibration displacement even under low voltage.

10 is a graph showing a simulated impedance versus frequency curve for a dome shaped linear piezo motor (DSPLM) according to another embodiment of the present invention.

Referring to FIG. 10, simulations were performed using the HP4194A to represent the impedance versus frequency curve. When the simulation results and the experimental data are compared, the vibration about the Z-axis in two parts between 50 and 100 kHz is shown. It can be seen that the displacement appears.

Here, the first resonant frequency range is similar to the general simulation result, but in the present invention, various types of resonant frequency curves are represented by the ceramic restraint body. In this case, displacements of various vibration modes with respect to the Z-axis can be obtained, and the efficiency thereof can be further improved.

The domed linear piezoelectric motor of the present invention, which provides excellent vibration displacement as described above, also provides stable displacement of the moving body. Hereinafter, the operation principle of the linear piezoelectric motor by interlocking the vibration shaft and the moving body will be described in more detail.

FIG. 11 is a graph illustrating a displacement of a moving body according to the inertia principle of a dome-shaped linear piezoelectric motor DSPLM, and FIG. 12 is a graph illustrating an electrical potential according to the displacement of FIG. 11.

As shown in FIG. 2B, the vibration shaft is fixed to one surface of the vibration shaft so as to be linked to the displacement of the piezoelectric ceramic actuator. Typically, one surface of the piezoelectric ceramic actuator faces the frame or housing of the motor, so that the vibration shaft is fixed to the opposite surface.

At this time, the mobile element is linearly driven by friction with the vibration shaft while being in contact with the shaft, and a predetermined pressing member such as a spring, a bolt, and a silicone rubber is placed on the contact portion between the mobile shaft and the vibration shaft. It is desirable to maintain a constant friction force using the.

When the vibrating shaft connected thereto is moved by the vibration of the piezoelectric ceramic actuator, the movable member moves along the moving direction of the vibrating shaft when the inertial force of the movable body is smaller than the frictional force with the vibrating shaft. It remains and only the vibration axis moves.

Here, a sawtooth wave-shaped driving voltage as shown in FIG. 12 is applied to the linear piezoelectric motor of the present invention.

When a sawtooth wave voltage is applied to the piezoelectric ceramic actuator, the oscillation axis of the piezoelectric ceramic actuator moves in the protruding direction in the sections (a-> b, c-> d, e-> f) (section A) where the voltage changes slowly. However, since it moves relatively slowly, the frictional force between the vibrating shaft and the moving body is greater than the inertial force of the moving body, and as a result, the vibrating shaft and the moving body move together (l _a- > l _b ).

On the contrary, in a section in which the voltage changes rapidly (b-> c, d-> e) (called section B), the oscillation axis of the piezoelectric ceramic actuator moves in the opposite direction to the protrusion direction but moves relatively quickly, so that the moving object's inertial force The friction force between the vibrating shaft and the moving body becomes larger, and as a result, the moving body slides on the vibrating shaft, so that only the vibrating shaft moves (l _b ).

As a result, as the section A and section B are repeated, the vibration displacement of the moving body accumulates and moves in the protruding direction. If a voltage having a phase difference of 180 ° from the sawtooth wave of FIG. 12 is applied, the vibration displacement of the moving body will accumulate in the opposite direction of the protruding direction and eventually move in the opposite direction of the protruding direction.

On the other hand, since the linear piezoelectric motor of the present invention further includes a ceramic restraint for supporting the piezoelectric ceramic actuator, the linear piezoelectric motor also serves to limit the displacement in the edge direction of the piezoelectric ceramic actuator to a predetermined size. At the center, the axial displacement can be further amplified.

FIG. 13 is a device for measuring a continuous displacement for a dome shaped linear piezoelectric motor (DSPLM) according to an embodiment of the present invention.

Referring to FIG. 13, a dome-shaped linear piezoelectric motor (DSPLM) 210 according to the present invention is placed under a micro laser interferometer (Cannon, DS-80A) having a resolution of 0.08 nm. A laser beam reflector and a load are mounted on the mobile element 220.

In addition, the piezoelectric ceramic actuator according to the present invention is connected to a power probe (Voltage probe, 230), the power probe is connected to a current control device (Driving circuit or I.C., 240) for applying an electric field.

In this case, a load of 10g or less is applied to the load, and an electric field of 60V _pp is applied within a resonance frequency range of 50kHz, and 5 pulses are applied to the displacement measurement.

14 is a graph showing the total displacement according to the application of the resonance frequency to the dome-shaped linear piezoelectric motor (DSPLM) according to an embodiment of the present invention.

Referring to FIG. 14, the continuous total displacement measured by the apparatus of FIG. 13 is shown as 15.6 μm. At this time, since the apparatus is applied for 5 pulses, the controllable displacement represented by the dome-shaped linear piezoelectric motor according to the present invention is 3.15 mu m.

As described above, the linear compression motor of the present invention employing a dome-type piezoelectric ceramic piezoelectric actuator with a ceramic restraint body has a maximum dome shape displacement of a dome shape as the size of an electric field increases. ) Up to 7.48 μm, and the continuous average displacement is also 3.12 μm, which is remarkably superior to that of a disk-shaped linear piezoelectric motor.

In the foregoing detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

1 is a photograph schematically showing a dome-shaped linear piezoelectric motor (DSPLM).

2A and 2B are photos and cross-sectional views schematically showing a dome-shaped linear piezoelectric motor (DSPLM) according to the present invention.

Figure 3 is a three-dimensional structural diagram for analysis of the dome-shaped piezoelectric actuator according to the present invention.

4 is a structural diagram for finite element analysis of a dome-shaped piezoelectric actuator according to the present invention.

5 is a graph showing a simulated impedance versus frequency curve for a dome shaped linear piezo motor (DSPLM) according to a comparative example of the present invention.

6 is a graph showing a simulated impedance versus frequency curve for a dome shaped linear piezoelectric motor (DSPLM) in accordance with one embodiment of the present invention.

7 is an ATILA three-dimensional simulation result of applying a resonance frequency to a dome-shaped linear piezoelectric motor (DSPLM) according to a comparative example of the present invention.

8 is an ATILA three-dimensional simulation result of applying a resonance frequency to a dome-shaped linear piezoelectric motor (DSPLM) according to an embodiment of the present invention.

9 is a graph showing the maximum vibration and applied voltage for the dome-shaped linear piezoelectric motor (DSPLM) according to an embodiment of the present invention.

10 is a graph showing a simulated impedance versus frequency curve for a dome shaped linear piezo motor (DSPLM) in accordance with another embodiment of the present invention.

11 is a graph showing the displacement of the moving body according to the inertia principle of the dome-shaped linear piezoelectric motor (DSPLM) according to an embodiment of the present invention.

12 is a graph showing the electrical potential according to the displacement of FIG.

13 is an apparatus for measuring a continuous displacement for a dome shaped linear piezoelectric motor (DSPLM) in accordance with one embodiment of the present invention.

14 is a graph showing the total displacement according to the application of the resonance frequency to the dome-shaped linear piezoelectric motor (DSPLM) according to an embodiment of the present invention.

Claims (10)

A dome-shaped piezoelectric ceramic actuator treated to apply different electrodes to both surfaces; A rod-shaped vibration shaft fixed perpendicularly to the upper vertex of the dome shape; A movable body fitted to the vibration shaft in a cylindrical shape and configured to linearly move along the vibration shaft; And Dome-shaped linear piezoelectric motor (DSPLM) characterized in that it comprises a ceramic restrainer fixed to the lower edge portion of the dome shape. The method of claim 1, And a pressing member which is formed on a surface of the movable body to maintain a constant frictional force at a contact portion between the movable body and the oscillation shaft. The method of claim 2, The pressing member is a dome-shaped linear piezoelectric motor, characterized in that made of any one selected from the spring, bolt and silicone rubber. The method of claim 1, And the ceramic restraint body is integrally formed with the piezoelectric ceramic actuator. The method of claim 1, The ceramic restraint body has a rigidity capable of constraining a radial vibration of the piezoelectric ceramic actuator, and is formed of a material having a thermal expansion coefficient similar to that of the piezoelectric ceramic actuator. The method of claim 1, The ceramic restraint body is a dome-shaped linear piezoelectric motor, characterized in that formed in a disk shape or a ring shape. The method of claim 1, And the ceramic constrainer is coupled to the piezoelectric ceramic actuator by a thermosetting adhesive. The method of claim 1, A dome shape further comprising a power source for applying an electric field to the piezoelectric ceramic actuator, an electric wire connecting the both sides of the power source and the piezoelectric ceramic actuator, and a solder to fix the electric wire to both sides of the piezoelectric ceramic actuator, respectively. Linear piezo motor. The method of claim 1, The piezoelectric ceramic actuator is a dome-shaped linear piezoelectric motor, characterized in that manufactured using 0.0 ₄ Pb (Sb _0.5 Nb _0.5 ) O ₃ -0.46PbTiO ₃ -0.5PbZrO ₃ composition. The method of claim 1, The piezoelectric ceramic actuator is a dome-shaped linear piezoelectric motor, characterized in that manufactured using a PIM (Powder Injection Molding) process.

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